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| author | Theodore Ts'o <tytso@mit.edu> | 2013-12-20 09:29:35 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-12-20 09:29:35 -0500 |
| commit | f5a44db5d2d677dfbf12deee461f85e9ec633961 (patch) | |
| tree | a60c763ab0cfc3a247f10ed36194d238b1e205bd /fs/ext4/ext4.h | |
| parent | 34cf865d54813aab3497838132fb1bbd293f4054 (diff) | |
| download | lwn-f5a44db5d2d677dfbf12deee461f85e9ec633961.tar.gz lwn-f5a44db5d2d677dfbf12deee461f85e9ec633961.zip | |
ext4: add explicit casts when masking cluster sizes
The missing casts can cause the high 64-bits of the physical blocks to
be lost. Set up new macros which allows us to make sure the right
thing happen, even if at some point we end up supporting larger
logical block numbers.
Thanks to the Emese Revfy and the PaX security team for reporting this
issue.
Reported-by: PaX Team <pageexec@freemail.hu>
Reported-by: Emese Revfy <re.emese@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/ext4.h')
| -rw-r--r-- | fs/ext4/ext4.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index e6185031c1cc..ece55565b9cd 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -268,6 +268,16 @@ struct ext4_io_submit { /* Translate # of blks to # of clusters */ #define EXT4_NUM_B2C(sbi, blks) (((blks) + (sbi)->s_cluster_ratio - 1) >> \ (sbi)->s_cluster_bits) +/* Mask out the low bits to get the starting block of the cluster */ +#define EXT4_PBLK_CMASK(s, pblk) ((pblk) & \ + ~((ext4_fsblk_t) (s)->s_cluster_ratio - 1)) +#define EXT4_LBLK_CMASK(s, lblk) ((lblk) & \ + ~((ext4_lblk_t) (s)->s_cluster_ratio - 1)) +/* Get the cluster offset */ +#define EXT4_PBLK_COFF(s, pblk) ((pblk) & \ + ((ext4_fsblk_t) (s)->s_cluster_ratio - 1)) +#define EXT4_LBLK_COFF(s, lblk) ((lblk) & \ + ((ext4_lblk_t) (s)->s_cluster_ratio - 1)) /* * Structure of a blocks group descriptor |